Terminal and transmission method

ABSTRACT

A terminal includes a receiver that receives an index specifying configuration information for transmitting a random access preamble; and a controller that configures, in response to the receiver receiving additional information that specifies a time domain resource for transmitting the random access preamble, the time domain resource specified by the additional information, the time domain resource being configured by replacing a time domain resource for transmitting the random access preamble included in the configuration information specified by the index with the time domain resource specified by the additional information.

TECHNICAL FIELD

The present invention relates to a terminal and a transmission method ina radio communication system.

BACKGROUND ART

In 3rd Generation Partnership Project (3GPP), a radio communicationsystem called New Radio (NR) or 5G has been studied to achieve a furtherincrease in a system capacity, a further increase in a data transmissionrate, and further reduction of latency in a radio section. In order toachieve a throughput that is greater than or equal to 10 Gbps, whilemeeting the requirement that the latency in the radio section is reducedto be less than or equal to 1 ms, various types of radio technology havebeen studied.

At the time at which the Release 15 specifications were fixed, thedl-UL-TransmissionPeriodicity of the TDD-UL-DL-pattern was 0.5 ms, 0.625ms, 1 ms, 1.25 ms, 2 ms, 2.5 ms, 5 ms, or 10 ms. In this regard, inorder to allow synchronization with DL/UL switching timings of LTE TDDconfigurations 1, 2, and 4, as the dl-UL-TransmissionPeriodicity, 3 msand 4 ms are added to the specifications subsequent to those ofSeptember, 2018.

RELATED ART DOCUMENT Non-Patent Document

Non-Patent Document 1: 3GPP T538.211 V15.6.0(2019-06)

Non-Patent Document 2: 3GPP TS36.211 V15.6.0(2019-06)

Non-Patent Document 3: 3GPP TSG-RAN WG2 Meeting #103, R2-1813303,Gothenburg, Sweden, 20-24 Aug. 2018 Non-Patent Document 4: 3GPP TSG-RANWG2 Meeting NR Adhoc 1807, R2-1810963, Montreal, Canada, 2-6 Jul. 2018

Non-Patent Document 5: 3GPP TSG-RAN WG2#103, R2-1813279, Gothenburg,Sweden, 20-24 Aug. 2018

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

Spectrum sharing between the LTE system and the NR system has beenassumed, i.e., a common frequency band has been assumed to be used inthe LTE system and the NR system. When timings of radio frames arealigned between the LTE TDD system and the NR TDD system, andcommunications are performed using a common frequency band, it isnecessary to suppress interference caused by one communication system onthe other communication system. For example, if an LTE TDD subframe isassigned to a downlink at a timing and an NR TDD subframe is assigned toan uplink at the timing, the NR uplink transmission may causesignificant interference on the LTE downlink reception.

There is a need for a method of suppressing interference caused by aterminal on another system when the terminal transmits a random accesspreamble.

Means for Solving the Problem

According to an aspect of the present invention, there is provided aterminal including a receiver that receives an index specifyingconfiguration information for transmitting a random access preamble; anda controller that configures, in response to the receiver receivingadditional information that specifies a time domain resource fortransmitting the random access preamble, the time domain resourcespecified by the additional information, the time domain resource beingconfigured by replacing a time domain resource for transmitting therandom access preamble included in the configuration informationspecified by the index with the time domain resource specified by theadditional information.

Advantage of the Invention

According to an embodiment of the present invention, there is provided amethod of suppressing interference caused by a terminal on anothersystem when the terminal transmits a random access preamble.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a configuration of a communicationsystem according to an embodiment.

FIG. 2 is a diagram illustrating an example of a random accessprocedure.

FIG. 3 is a diagram illustrating an example of a random accessconfiguration table.

FIG. 4 is a diagram illustrating an example of an Uplink-downlinkconfiguration for an LTE TDD system.

FIG. 5 is a diagram illustrating an example of Proposal 1.

FIG. 6 is a diagram illustrating an example of a RACH-ConfigGenericinformation element.

FIG. 7 is a diagram illustrating a modified example of a specificationcorresponding to Proposal 1.

FIG. 8 is a diagram illustrating an example of Proposal 2.

FIG. 9 is a diagram illustrating an example of a RACH-ConfigGenericinformation element.

FIG. 10 is a diagram illustrating a modified example of a specificationcorresponding to Proposal 2.

FIG. 11 is a diagram illustrating an example of a RACH-ConfigGenericinformation element.

FIG. 12 is a diagram illustrating a modified example of a specificationcorresponding to Proposal 3.

FIG. 13 is a diagram illustrating an example of a RACH-ConfigGenericinformation element.

FIG. 14 is a diagram illustrating a modified example of a specificationcorresponding to Proposal 4.

FIG. 15 is a diagram illustrating an example of Proposal 5.

FIG. 16 is a diagram illustrating an example of a RACH-ConfigGenericinformation element.

FIG. 17 is a diagram illustrating a modified example of a specificationcorresponding to Proposal 5.

FIG. 18 is a diagram illustrating an example of Proposal 6.

FIG. 19 is a diagram illustrating an example of a RACH-ConfigGenericinformation element.

FIG. 20 is a diagram illustrating a modified example of a specificationscorresponding to Proposal 6.

FIG. 21 is a diagram illustrating an example of a functionalconfiguration of a terminal.

FIG. 22 is a diagram illustrating an example of a functionalconfiguration of a base station.

FIG. 23 is a diagram illustrating an example of a hardware configurationof a terminal and a base station.

EMBODIMENTS OF THE INVENTION

In the following, embodiments of the present invention (the embodiments)are described with reference to the drawings. The embodiments describedbelow are merely examples, and embodiments to which the presentinvention is applied are not limited to the following embodiments.

The radio communication system according to the following embodiments isassumed to basically conform to NR, but this is an example, and anentire radio communication system or a part of the radio communicationsystem according to the embodiments may conform to a radio communicationsystem other than NR (e.g., LTE).

Overall System Configuration

FIG. 1 is a configuration diagram of the radio communication systemaccording to an embodiment. The radio communication system according tothe embodiment includes a terminal (user equipment) 10 and a basestation 20 as illustrated in FIG. 1. In FIG. 1, one terminal 10 and onebase station 20 are indicated, but this is an example and there may betwo or more terminals 10 and two or more base stations 20.

The terminal 10 is a communication device having a radio communicationfunction, such as a smartphone, a cellular phone, a tablet, a wearableterminal, and a communication module for M2M (Machine-to-Machine). Theterminal 10 wirelessly connects to the base station 20 and utilizesvarious communication services provided by the radio communicationsystem. The base station 20 is a communication device that provides oneor more cells and wirelessly communicates with the terminal 10. Theterminal 10 and the base station 20 are capable of beam forming totransmit and receive signals. The terminal 10 may also be referred to asa UE and the base station 20 may be referred to as an eNB.

In an embodiment, a duplex method may be a TDD (Time Division Duplex)method or a FDD (Frequency Division Duplex) method.

The technology according to an embodiment relates to a random accessprocedure or the like. Accordingly, first, these operation examples inthe radio communication system are described.

Random Access Procedures

Referring to FIG. 2, an example of a random access procedure accordingto this embodiment is described. The procedure illustrated in FIG. 2 mayalso be referred to as an initial access.

The base station 20 transmits a Synchronization Signals and PhysicalBroadcast Channel (SS/PBCH) block (also called SSB) at a predeterminedperiod, and the terminal 10 receives the SS/PBCH block (S11). TheSS/PBCH block includes a synchronization signal, a part of systeminformation required for an initial access (a system frame number (SFN),information required to read remaining system information, etc.). Theterminal 10 receives a System Information Block 1 (SIB1) from the basestation 20 (S12).

Subsequently, the terminal 10 transmits Message1 (Msg1(=RA preamble))(S13).

In response to detecting an RA preamble, the base station 20 transmits aresponse, i.e., a Message2 (Msg2(=RA response)) to the terminal 10(S14). In the following description, “Msg2” includes a Physical DownlinkControl Channel (PDCCH) used for scheduling and a Physical DownlinkShared Channel (PSDCH) for transmitting main body information.

In response to receiving the RA response, the terminal 10 transmits aMessage3 (Msg3) including predetermined information to the base station20 (step S15). For example, a Message 3 is an RRC connection request.

In response to receiving the Message 3, the base station 20 transmits aMessage4 (Msg4, e.g., RRC connection setup) to the terminal 10 (S16).Upon detecting that the above-described predetermined information isincluded in the Message4, the terminal 10 determines that the Message4corresponds to the above-described Message3 and the Message4 isaddressed to the terminal 10, the terminal 10 completes the randomaccess procedure, and the terminal 10 establishes an RRC connection(S17). Note that FIG. 2 illustrates an example of a case in which theMessage3 and Message4 are transmitted. However, this is merely anexample. The technique according to an embodiment can be applied to arandom access procedure in which a Message3 and a Message4 are nottransmitted.

As for a transmission occasion of a random access preamble, it isspecified in Non-Patent Document 1 that a random access preamble can betransmitted only during the time resource specified by a higher layerparameter prach-ConfigIndex.

FIG. 3 is a diagram illustrating an example of a table of a randomaccess configurations specified by a prach-ConfigIndex for a FrequencyRange (FR) 1 and a TDD.

For example, suppose that a value 0 is transmitted from the base station20 to the terminal 10, as a PRACH Configuration Index. In this case, inresponse to receiving the value 0 as the PRACH Configuration Index, theterminal 10 can detect that a preamble format is 0; periodicity of atransmission occasion of a random access preamble is 160 ms; and atransmission occasion of a random access preamble is the subframe 9among subframes 0 to 9 included in a radio frame of 10 ms.

The n_(SFN) mod x=y illustrated in FIG. 3 specifies a radio frame numberthat includes a transmission occasion of a random access preamble. Forexample, when x=16 and y=1, transmission occasions of a random accesspreamble are radio frames with system frame number (SFN)=1, 17, 33, . .. Because the duration of one radio frame is 10 ms, when x=16 and y=1,the periodicity of transmission occasions of a random access preamble is160 ms. In the example of FIG. 3, when the value of the PRACHConfiguration Index is 1, the periodicity of transmission occasions of arandom access preamble is 80 ms; when the value of the PRACHConfiguration Index is 2, the periodicity of transmission occasions of arandom access preamble is 40 ms; and when the value of the PRACHConfiguration Index is any of 3 to 6, the periodicity of transmissionoccasions of a random access preamble is 20 ms.

FIG. 4 is a diagram illustrating an example of an Uplink-downlinkconfiguration for the time division duplex (TDD) method of LTE. In theexample illustrated in FIG. 4, 10 subframes are included in a radioframe of 10 ms, and each subframe is a downlink subframe (indicated asD), an uplink subframe (indicated as U), or a special subframe(indicated as S).

Problem

At the time at which the 3GPP Release 15 specifications were fixed, thedl-UL-TransmissionPeriodicity of TDD-UL-DL-pattern was 0.5 ms, 0.625 ms,1 ms, 1.25 ms, 2 ms, 2.5 ms, 5 ms, or 10 ms.

In this regard, in order to allow synchronization with DL/UL switchingtimings of LTE TDD configurations 1, 2, and 4, as thedl-UL-TransmissionPeriodicity, 3 ms and 4 ms are added to thespecifications subsequent to those of September, 2018. As describedabove, it is assumed that a radio frame timing of the LTE TDD system isaligned with a radio frame timing of the NR TDD system. Furthermore,spectrum sharing between the LTE system and the NR system has beenassumed, i.e., a common frequency band has been assumed to be used inthe LTE system and the NR system.

When timings of radio frames are aligned between the LTE TDD system andthe NR TDD system, and communications are performed using a commonfrequency band, it is necessary to suppress interference caused by onecommunication system on the other communication system. For example, ifan LTE TDD subframe is assigned to a downlink at a timing and an NR TDDsubframe is assigned to an uplink at the timing, the NR uplinktransmission may cause significant interference on the LTE downlinkreception. Accordingly, when the LTE TDD system and the NR TDD systemare used in a common frequency band, it is assumed that an LTE TDDsubframe and an NR TDD subframe at a timing that is the same as the LTETDD subframe are assigned for uplink, or downlink.

Here, suppose that a timing of a radio frame of the LTE TDD system isaligned with a timing of a radio frame of the NR TDD system and thatspectrum sharing is performed between the LTE system and NR system.Furthermore, suppose that, in the LTE system, 2 is configured as theUplink-downlink configuration illustrated in FIG. 4. In this case, amongthe radio frames of the LTE system, the subframes assigned to uplink aresubframe 2 and subframe 7.

Accordingly, when the terminal 10 transmits a random access preamble inthe NR system, it is assumed that the terminal 10 transmits the randomaccess preambles in the subframe 2 and/or the subframe 7.

However, according to the table illustrated in FIG. 3, when the PRACHConfiguration Index is any one of 0 to 6, subframes for transmitting arandom access preamble are 9 and 4, and it is not assumed that subframes2 and 7 are to be specified.

There is a need for a method of allowing the terminal 10 in the NRsystem to transmit a random access preamble at a timing of a subframethat is specified for uplink in the LTE system.

Proposal 1

FIG. 5 is a diagram illustrating an example of Proposal 1. In the methodof Proposal 1, the table that specifies the random access configurationsillustrated in FIG. 3 is used as is (the table illustrated in FIG. 3itself is not changed). For example, the base station 20 notifies theterminal 10 of any index among the PRACH Configuration Indexes 0-6 ofthe table illustrated in FIG. 3. Furthermore, the base station 20notifies the terminal 10 of the subframe number specifying the randomaccess preamble transmission occasion by RRC signaling. The terminal 10does not apply the subframe number specified in the table illustrated inFIG. 3, but applies the subframe number received from the base station20 as a transmission occasion of a random access preamble.

For example, the base station 20 transmits a value 0 as the PRACHConfiguration Index to the terminal 10. Furthermore, the base station 20notifies the terminal 10, for example, that the subframe numberspecifying a random access preamble transmission occasion is 7. Theterminal 10 receives the value 0 as the PRACH Configuration Index andconfigures the subframe 7 as a subframe capable of transmitting a randomaccess preamble in response to receiving the subframe number 7specifying a random access preamble transmission occasion. In this case,the radio frame in which a random access preamble can be transmitted isSFN=1, 17, 33, . . . That is, the terminal 10 configures 160 ms, as theperiodicity of transmission occasions of a random access preamble.

FIG. 6 is a diagram illustrating an example of a RACH-ConfigGenericinformation element that can be used by the base station 20 to notifythe terminal 10 of a subframe number specifying a random access preambletransmission occasion. The value of the field prach-Subframe included inthe RACH-ConfigGeneric information element illustrated in FIG. 6 mayspecify a subframe number of a subframe in which a random accesspreamble can be transmitted. FIG. 7 is a diagram illustrating a modifiedexample of the specification corresponding to Proposal 1.

Proposal 2

FIG. 8 is a diagram illustrating an example of Proposal 2. In the methodof Proposal 2, the table specifying the random access configurationsillustrated in FIG. 3 is used without any modification (the tableillustrated in FIG. 3 itself is not changed). For example, the basestation 20 notifies the terminal 10 of any index among the PRACHConfiguration Indexes 0-6 of the table illustrated in FIG. 3.Furthermore, the base station 20 notifies the terminal 10 of the offsetbetween a subframe number specified in the table of FIG. 3 and asubframe number of a subframe that is actually capable of transmitting arandom access preamble by RRC signaling. The terminal 10 sets a numberobtained by applying the modulo 10 calculation to the value obtained byadding the offset value to the subframe number specified in the tableillustrated in FIG. 3, as the subframe number of the subframe capable oftransmitting a random access preamble.

For example, the base station 20 transmits a value 0 as the PRACHConfiguration Index to the terminal 10. Furthermore, the base station 20notifies the terminal 10 of 8 by RRC signaling, as an offset valuebetween a subframe number specified in the table of FIG. 3 and asubframe number of a subframe in which a random access preamble canactually be transmitted. The terminal 10 receives the value 0 as thePRACH Configuration Index and, in response to receiving 8 as the offsetvalue between the subframe number specified in the table of FIG. 3 andthe subframe number of the subframe in which a random access preamblecan be actually transmitted, calculates (9+8) mod 10=7 and sets thesubframe 7 as a subframe in which a random access preamble can betransmitted. In this case, the radio frames in which a random accesspreamble can be transmitted are SFN=1, 17, 33, . . . That is, theterminal 10 sets 160 ms, as the periodicity of transmission occasions ofa random access preamble.

FIG. 9 is a diagram illustrating an example of a RACH-ConfigGenericinformation element that can be used by the base station 20 fornotifying the terminal 10 of an offset between a subframe numberspecified in the table of FIG. 3 and a subframe number of a subframe inwhich a random access preamble can be actually transmitted. The valuesof the field prach-Subframe included in the RACH-ConfigGenericinformation element illustrated in FIG. 9 may specify the offset betweenthe subframe number specified in the table in FIG. 3 and the subframenumber of the subframe that is actually capable of transmitting randomaccess preambles. FIG. 10 is a diagram illustrating a modified exampleof the specification corresponding to Proposal 2.

Proposal 3

When the base station 20 attempts to configure any one of the PRACHConfiguration Indexes 0-6 illustrated in FIG. 3 for the terminal 10, forexample, a PRACH Configuration IndexAlt may be defined, as an index thatis different from the PRACH Configuration Index illustrated in FIG. 3,while assuming a case in which only a subframe number is set to 2 or 7,instead of 4 or 9. The base station 20 may set any value from 0 to 6 asthe PRACH Configuration IndexAlt and notify the terminal 10 of the PRACHConfiguration IndexAlt by RRC signaling. Additionally, the base station20 may notify the terminal 10 of a subframe number 2 or 7 by RRCsignaling. In this case, for example, it is possible to set only thesubframe number of the subframe in which the random access preamble canbe transmitted to 2 or 7, instead of 4 or 9, while configuring a randomaccess resource corresponding to any one of the PRACH ConfigurationIndexes 0-6 illustrated in FIG. 3 without changing the table of FIG. 3itself. As described above, when the new parameter PRACH ConfigurationIndexAlt is defined, a legacy terminal does not read the PRACHConfiguration IndexAlt but reads only the PRACH Configuration Index.Accordingly, it is possible to apply different PRACH ConfigurationIndexes to the legacy terminal and the terminal 10 that supports themethod of Proposed 3, respectively, and the legacy terminal and theterminal 10 supporting the method of Proposal 3 can coexist.

FIG. 11 is a diagram illustrating an example of a RACH-ConfigGenericinformation element that can be used by the base station 20 fornotifying the terminal 10 of the PRACH Configuration IndexAlt and thesubframe number. By setting the value of the fieldprach-ConfigurationIndexAlt included in the RACH-ConfigGenericinformation element illustrated in FIG. 11 to any value from 0 to 6 andsetting the subframe number (the value of the field prach-Subframe inFIG. 11) to 2 or 7, the base station 20 can set, to the terminal 10,only the subframe number to 2 or 7, instead of 9, while configuring arandom access configuration corresponding to any one of the PRACHConfiguration Indexes 0 to 6 illustrated in FIG. 3 for the terminal 10.That is, upon receiving the PRACH-ConfigGeneric information element, theterminal 10 determines whether the field of prach-ConfigurationIndexAltis included. In response to detecting that the PRACH-ConfigGenericinformation element includes a prach-ConfigurationIndexAlt field, theterminal 10 obtains any value from 0 to 6 set in theprach-ConfigurationIndexAlt field, and obtains 2 or 7, as a subframenumber. As a result, the terminal 10 can configure a random accessresource corresponding to the PRACH Configuration Index corresponding tothe value set in the prach-ConfigurationIndexAlt field while setting 2or 7 as the subframe number of the subframe in which a random accesspreamble can be transmitted. FIG. 12 is a diagram illustrating amodified example a specification corresponding to Proposal 3.

Proposal 4

When the base station 20 attempts to set any of the PRACH ConfigurationIndexes 0-6 illustrated in FIG. 3 to the terminal 10, for example, aPRACH Configuration IndexAlt may be defined, as an index that isdifferent from the PRACH Configuration Index illustrated in FIG. 3,while assuming a case in which only a subframe number is set to 2 or 7,instead of 4 or 9. The base station 20 may set any value of the valuesfrom 0 to 6 as the PRACH Configuration IndexAlt and notify the terminal10 of the PRACH Configuration IndexAlt by RRC signaling. Additionally,the base station 20 notifies the terminal 10 of the offset between thesubframe number specified in the table of FIG. 3 and the subframe numberof the subframe that is actually capable of transmitting the randomaccess preamble by RRC signaling. In this case, it is possible to setonly the subframe number of the subframe in which the random accesspreamble can be transmitted to 2 or 7 instead of 4 or 9 whileconfiguring a random access resource corresponding to any one of thePRACH Configuration Indexes 0-6 illustrated in FIG. 3, without changingthe table in FIG. 3 itself. As described above, when the new parameterPRACH Configuration IndexAlt is defined, the legacy terminal does notread the PRACH Configuration IndexAlt but reads only the PRACHConfiguration Index. Accordingly, it is possible to apply differentPRACH Configuration Indexes to the legacy terminal and the terminal 10supporting the method of Proposed 3. The legacy terminal and theterminal 10 supporting the method of Proposed 3 can coexist.

FIG. 13 is a diagram illustrating an example of a RACH-ConfigGenericinformation element that can be used by the base station 20 fornotifying the terminal 10 of the PRACH Configuration IndexAlt and thesubframe number. By setting the value of the fieldprach-ConfigurationIndexAlt included in the RACH-ConfigGenericinformation element illustrated in FIG. 11 to any value from 0 to 6 andsetting the offset value of the subframe number (the value of the fieldprach-SubframeOffset illustrated in FIG. 13) to 3 or 8, the base station20 can set only the subframe number to 2 or 7 instead of 4 or 9 whileconfiguring a random access configuration corresponding to any one ofthe PRACH Configuration Indexes 0 to 6 illustrated in FIG. 3 to theterminal 10. Upon receiving the PRACH-ConfigGeneric information element,the terminal 10 determines whether a prach-ConfigurationIndexAlt fieldis included. In response to detecting that thePRACH-ConfigurationIndexAlt field is included in the PRACH-ConfigGenericinformation element, the terminal 10 obtains a value from 0 to 6 set inthe prach-ConfigurationIndexAlt field, and in response to receiving 3 or8 as the offset value of the subframe number, calculates (3+9) mod 10=2or (8+9) mod 10=7 (or (3+4) mod 10=7 or (8+4) mod 10=2), and sets thesubframe 2 or 7 as a subframe capable of transmitting a random accesspreamble. FIG. 14 is a diagram illustrating a modified example of thespecification corresponding to Proposal 4.

Proposal 5

The random access configuration table for the FR1 and TDD illustrated inFIG. 3 may be extended to include a PRACH Configuration Indexcorresponding to any of the PRACH Configuration Indexes 0-6 illustratedin FIG. 3, while only the subframe number is modified to be 2 or 7,instead of 4 or 9. FIG. 15 is a diagram illustrating an example ofProposed 5. In the table illustrated in FIGS. 15, 256 to 271 are addedas PRACH Configuration Indexes, and by any one of Indexes 256 to 269, arandom access configuration corresponding to any one of PRACHConfiguration Indexes 0 to 6 while only the subframe number is modifiedto be 2 or 7, instead of 4 or 9. An extension may also be made so thatthe base station 20 can transmit the PRACH Configuration Index that is avalue greater than or equal to 256 in the RACH-ConfigGeneric informationelement that can be used to notify the terminal 10 of the PRACHConfiguration Index.

FIG. 16 is a diagram illustrating an example of a RACH-ConfigGenericinformation element that can be used by the base station 20 to notifythe terminal 10 of the PRACH Configuration Index. By using theprach-ConfigurationIndex-v16xy field included in the RACH-ConfigGenericinformation element illustrated in FIG. 16, a notification of the PRACHConfiguration Index with a value that is greater than or equal to 256can be transmitted. FIG. 17 is a diagram illustrating a modified exampleof the specification corresponding to Proposal 5.

Proposal 6

FIG. 18 is a diagram illustrating an example of Proposal 6. In themethod of Proposal 6, a table is newly defined that corresponds to thetable for specifying a random access configuration illustrated in FIG. 3and that can specify a subframe number 2 or 7, as a subframe in which arandom access preamble can be transmitted. In the table illustrated inFIG. 18, indexes 0 to 6 corresponding to the PRACH Configuration Indexesillustrated in FIG. 3 and capable of specifying subframe number 2, andindexes 7 to 13 corresponding to the PRACH Configuration Indexesillustrated in FIG. 3 and capable of specifying subframe number 7 aredefined.

FIG. 19 is a diagram illustrating an example of a RACH-ConfigGenericinformation element that can be used by the base station 20 fornotifying the PRACH Configuration Index to the terminal 10. By using thefield prach-ConfigurationIndexAlt included in the RACH-ConfigGenericinformation element illustrated in FIG. 19, a notification of a PRACHConfiguration Index that corresponds to the PRACH Configuration Indexillustrated in FIG. 3 and that can specify a subframe number 2 or 7 canbe transmitted. FIG. 20 is a diagram illustrating a modified example ofthe specification corresponding to Proposal 6.

As described in the above embodiments, an NR time domain resourcespecified by a PRACH Configuration Index, which is capable oftransmitting a random access preamble, may only be enabled if the timingmatches the timing of an LTE UL transmission resource for unpairedspectrum (TDD).

The UE capability corresponding to the above-described extensions ofProposal 1 to Proposal 6 may be specified. As for the terminal 10 in aconnected mode, e.g., the terminal 10 supporting EN-DC, aRACH-ConfigGeneric based on any one of Proposal 1 to Proposal 6 may beset to the terminal 10 based on the UE capability.

According to the above-described embodiments, when the timings of TDD ULDL configurations are matched between the LTE TDD system and the NR TDDsystem, the system of the NR can support any RACH periodicity of 20 ms,40 ms, 80 ms, and 160 ms.

Device Configuration

Next, a functional configuration example of the base station 20 and theterminal 10 for performing the processes and operations described aboveis described. The base station 20 and the terminal 10 include functionsfor implementing the above-described embodiments. However, each of thebase station 20 and the terminal 10 may include only a part of thefunctions in the embodiments. The terminal 10 and the base station 20may be collectively referred to as a communication device.

<User Equipment>

FIG. 21 is a diagram illustrating an example of a functionalconfiguration of the terminal 10. As illustrated in FIG. 21, theterminal 10 includes a transmitter 110, a receiver 120, and a controller130. The functional configuration illustrated in FIG. 21 is merely anexample. The functional division and names of functional units may beany division and names, provided that the operation according to theembodiments can be performed. Note that the transmitter 110 may bereferred to as a transmitter, and the receiver 120 may be referred to asa receiver.

The transmitter 110 creates a transmission signal from transmission dataand transmits the transmission signal through radio. The transmitter 110can form one or more beams. The receiver 120 receives various types ofsignals wirelessly and obtains higher layer signals from the receivedphysical layer signals. Furthermore, the receiver 120 includes ameasurement unit that measures a received signal to obtain receivedpower, etc.

The controller 130 performs control of the terminal 10. The function ofthe controller 130 related to transmission may be included in thetransmitter 110, and the function of the controller 130 related toreception may be included in the receiver 120.

For example, the receiver 120 of the terminal 10 receives a signalincluding a PRACH Configuration Index transmitted from the base station20. The controller 130 of the terminal 10 configures the preamble formatcorresponding to the value of the PRACH Configuration Index received bythe receiver 120, periodicity of transmission occasions of a randomaccess preamble, and a subframe number including a transmission occasionof a random access preamble. The transmitter 110 of the terminal 10transmits a random access preamble to the base station 20 according tothe random access configuration configured by the controller 130.

For example, the receiver 120 of the terminal 10 receives a signalincluding the PRACH Configuration Index transmitted from the basestation 20. The receiver 120 of the terminal 10 receives an additionalsignal including a subframe number specifying a transmission occasion ofa random access preamble. The controller 130 of the terminal 10configures the preamble format corresponding to the value of thereceived PRACH Configuration Index and periodicity of transmissionoccasions of a random access preamble. However, for the transmissionoccasions of a random access preamble, the controller 130 sets asubframe number specified by an additional signal received by thereceiver 120.

For example, the receiver 120 of the terminal 10 receives a signalincluding the PRACH Configuration Index transmitted from the basestation 20. The receiver 120 of the terminal 10 receives an additionalsignal including an offset between the subframe number of the subframespecified by the PRACH Configuration Index received by the receiver 120and the subframe number of the subframe in which the random accesspreamble can be actually transmitted. The controller 130 of the terminal10 configures the preamble format corresponding to the value of thereceived PRACH Configuration Index and periodicity of transmissionoccasions of a random access preamble. However, for the transmissionoccasions of a random access preamble, the controller 130 sets asubframe number specified by an additional signal received by thereceiver 120.

For example, the receiver 120 of the terminal 10 receives a signalincluding an alternative PRACH Configuration Index transmitted from thebase station 20. The receiver 120 of the terminal 10 receives anadditional signal including a subframe number specifying a transmissionoccasion of a random access preamble. The controller 130 of the terminal10 configures the preamble format specified by a normal PRACHConfiguration Index corresponding to the value of the alternative PRACHConfiguration Index received by the receiver 120 and periodicity oftransmission occasions of a random access preambles. However, for thetransmission occasions of a random access preamble, the controller 130sets a subframe number specified by an additional signal received by thereceiver 120.

For example, the receiver 120 of the terminal 10 receives a signalincluding an alternative PRACH Configuration Index transmitted from thebase station 20. The receiver 120 of the terminal 10 receives anadditional signal including an offset between the subframe number of thesubframe specified by the normal PRACH Configuration Index correspondingto the value of the alternative PRACH Configuration Index received bythe receiver 120 and the subframe number of the subframe in which arandom access preamble can actually be transmitted. The controller 130of the terminal 10 configures a preamble format specified by the normalPRACH Configuration Index corresponding to a value of the alternativePRACH Configuration Index received by the receiver 120 and periodicityof transmission occasions of a random access preamble. However, for thetransmission occasions of a random access preamble, the controller 130sets a subframe number specified by an additional signal received by thereceiver 120.

For example, the receiver 120 of the terminal 10 receives a signalincluding an additional PRACH Configuration Index transmitted from thebase station 20. In this case, the controller 130 of the terminal 10configures the preamble format, periodicity of transmission occasions ofa random access preamble, and a subframe number as the transmissionoccasion of a random access preamble corresponding to the value of thePRACH Configuration Index received by the receiver 120.

For example, a first table including a first set of normal PRACHConfiguration Indexes and a second table including a second set of PRACHConfiguration Indexes corresponding to the first set of the normal PRACHConfiguration Indexes, but specifying a subframe number other than thosespecified in the first set of the normal PRACH Configuration Indexes, asthe subframe number of the subframe in which a random access preamblecan be transmitted, may be defined. In this case, for example, thereceiver 120 of the terminal 10 receives a signal including one of thePRACH Configuration Indexes of the second set transmitted from the basestation 20. The controller of the terminal 10 configures the preambleformat, periodicity of transmission occasions of a random accesspreamble, and a subframe number as a transmission occasion of a randomaccess preamble corresponding to the value of any of the PRACHConfiguration Indexes of the second set received by the receiver 120.

<Base Station 20>

FIG. 22 is a diagram illustrating an example of a functionalconfiguration of the base station 20. As illustrated in FIG. 22, thebase station 20 includes a transmitter 210, a receiver 220, and acontroller 230. The functional configuration illustrated in FIG. 22 ismerely one example. The function division and the names of thefunctional units may be any division and names, provided that theoperation according to the embodiments can be implemented. Note that thetransmitter 210 may be referred to as a transmitter and the receiver 220may be referred to as a receiver.

The transmitter 210 includes a function for generating a signal to betransmitted to the terminal 10 and transmitting the signal throughradio. The transmitter 210 forms one or more beams. The receiver 220includes a function for receiving various signals transmitted from theterminal 10 and obtaining, for example, information of a higher layerfrom the received signals. The receiver 220 includes a measurement unitthat measures a received signal to obtain received power or the like.

The controller 230 controls the base station 20. The function of thecontroller 230 related to transmission may be included in thetransmitter 210, and the function of the controller 230 related toreception may be included in the receiver 220.

For example, the controller 230 of the base station 20 selects a PRACHConfiguration Index for specifying a random access configuration to beconfigured for the terminal 10. The transmitter 210 of the base station20 transmits a signal including the PRACH Configuration Index selectedby the controller 230 to the terminal 10. Additionally, when a subframenumber specifying a transmission occasion of a random access preambleconfigured by the PRACH Configuration Index to be transmitted to theterminal 10 is modified, the controller 230 of the base station 20generates information specifying the modified subframe number, and thetransmitter 210 transmits a signal including information specifying themodified subframe number to the terminal 10.

<Hardware Configuration>

The block diagrams (FIG. 21 to FIG. 22) used for the description of theabove embodiments show blocks of functional units. These functionalblocks (components) are implemented by any combination of at least oneof hardware and software. In addition, the implementation method of eachfunctional block is not particularly limited. That is, each functionalblock may be implemented using a single device that is physically orlogically combined, or may be implemented by directly or indirectlyconnecting two or more devices that are physically or logicallyseparated (e.g., using wire or radio) and using these multiple devices.The functional block may be implemented by combining software with theabove-described one device or the above-described plurality of devices.Functions include, but are not limited to, judgment, decision,determination, computation, calculation, processing, derivation,research, search, verification, reception, transmission, output, access,resolution, choice, selection, establishment, comparison, assumption,expectation, deeming, broadcasting, notifying, communicating,forwarding, configuring, reconfiguring, allocating, mapping, assigning,or the like. For example, a functional block (component) that functionsto transmit is called a transmitter or a transmitter. In either case, asdescribed above, the implementation method is not particularly limited.

For example, the terminal 10 and the base station 20 according to anembodiment of the present invention may function as a computer thatperforms processing according to the present embodiment. FIG. 23 is adiagram illustrating an example of a hardware configuration of theterminal 10 and the base station 20 according to the present embodiment.The terminal 10 and the base station 20 may each be configured as acomputer device including, physically, a processor 1001, memory 1002, astorage 1003, a communication device 1004, an input device 1005, anoutput device 1006, a bus 1007, or the like.

In the following description, the term “device” can be replaced with acircuit, a device, a unit, or the like. The hardware configuration ofthe terminal 10 and base station 20 may be configured to include one ormore of the devices denoted by 1001-1006 in the figure, or may beconfigured without some devices.

Each function of the terminal 10 and the base station 20 is implementedby loading predetermined software (program) on hardware, such as theprocessor 1001 and the memory 1002, so that the processor 1001 performscomputation and controls communication by the communication device 1004,and at least one of reading and writing of data in the memory 1002 andthe storage 1003.

The processor 1001, for example, operates an operating system to controlthe entire computer. The processor 1001 may be configured with a centralprocessing unit (CPU: Central Processing Unit) including an interfacewith a peripheral device, a control device, a processing device, aregister, or the like.

Additionally, the processor 1001 reads a program (program code), asoftware module, data, or the like from at least one of the storage 1003and the communication device 1004 to the memory 1002, and executesvarious processes according to these. As the program, a program is usedwhich causes a computer to execute at least a part of the operationsdescribed in the above-described embodiment. For example, the controller130 of the terminal 10 may be implemented by a control program that isstored in the memory 1002 and that is operated by the processor 1001,and other functional blocks may be similarly implemented. While thevarious processes described above are described as being executed in oneprocessor 1001, they may be executed simultaneously or sequentially bytwo or more processors 1001. The processor 1001 may be implemented byone or more chips. The program may be transmitted from a network via atelecommunications line.

The memory 1002 is a computer readable storage medium, and, for example,the memory 1002 may be formed of at least one of a Read Only Memory(ROM), an Erasable Programmable ROM (EPROM), an Electrically ErasableProgrammable ROM (EEPROM), a RAM (Random Access Memory), or the like.The memory 1002 may be referred to as a register, a cache, a main memory(main storage device), or the like. The memory 1002 may store a program(program code), a software module, or the like which can be executed forimplementing the radio communication method according to one embodimentof the present disclosure.

The storage 1003 is a computer readable storage medium and may be formedof, for example, at least one of an optical disk, such as a Compact DiscROM (CD-ROM), a hard disk drive, a flexible disk, an optical magneticdisk (e.g., a compact disk, a digital versatile disk, a Blu-ray(registered trademark) disk, a smart card, a flash memory (e.g., a card,a stick, a key drive), a floppy (registered trademark) disk, a magneticstrip, or the like. The storage 1003 may be referred to as an auxiliarystorage device. The above-described storage medium may be, for example,a database including at least one of the memory 1002 and the storage1003, a server, or any other suitable medium.

The communication device 1004 is hardware (transmitting and receivingdevice) for performing communication between computers through at leastone of a wired network and a wireless network, and is also referred to,for example, as a network device, a network controller, a network card,a communication module, or the like. The communication device 1004 maybe configured to include, for example, a high frequency switch, aduplexer, a filter, a frequency synthesizer, or the like to implement atleast one of frequency division duplex (FDD: Frequency Division Duplex)and time division duplex (TDD: Time Division Duplex).

The input device 1005 is an input device (e.g., a keyboard, a mouse, amicrophone, a switch, a button, or a sensor) that receives an externalinput. The output device 1006 is an output device (e.g., a display,speaker, or LED lamp) that performs output toward outside. The inputdevice 1005 and the output device 1006 may be configured to beintegrated (e.g., a touch panel).

Each device, such as processor 1001 and memory 1002, is also connectedby the bus 1007 for communicating information. The bus 1007 may beformed of a single bus or may be formed of different buses betweendevices.

The terminal 10 and base station 20 may each include hardware, such as amicroprocessor, a digital signal processor (DSP: Digital SignalProcessor), an Application Specific Integrated Circuit (ASIC), aProgrammable Logic Device (PLD), and a Field Programmable Gate Array(FPGA), which may implement some or all of each functional block. Forexample, processor 1001 may be implemented using at least one of thesehardware components.

Conclusion of the Embodiments

In this specification, at least the terminal and the communicationmethod described below are disclosed.

A terminal including a receiver that receives an index specifyingconfiguration information for transmitting a random access preamble; anda controller that configures, in response to the receiver receivingadditional information that specifies a time domain resource fortransmitting the random access preamble, the time domain resourcespecified by the additional information, the time domain resource beingconfigured by replacing a time domain resource for transmitting therandom access preamble included in the configuration informationspecified by the index with the time domain resource specified by theadditional information. According to the above-described configuration,for example, in a case where a time domain resource for transmitting arandom access preamble included in default configuration information fortransmitting the random access preamble overlaps a timing of a timedomain resource for a downlink transmission in another system, the timedomain resource for transmitting the random access preamble can beconfigured to be another time domain resource specified by theadditional information. By matching the other time domain resourcespecified by the additional information with a timing of a time domainresource for an uplink transmission in another communication system, aneffect of an interference on the other communication system caused by arandom access preamble transmission can be reduced.

The time domain resource for transmitting the random access preamble maybe a resource in a unit of a subframe, and the additional informationmay specify one of a subframe number of a subframe for transmitting therandom access preamble or an offset value between a subframe number of asubframe specified by the configuration and a subframe number of asubframe that is actually capable of transmitting the random accesspreamble.

According to the above-described configuration, for example, when an LTETDD system and an NR TDD system are used in a common frequency band, byspecifying a subframe for transmitting a random access preamble by theadditional information, the subframe for transmitting the random accesspreamble can be adjusted to the timing of an LTE uplink subframe.Accordingly, an effect of an interference on the LTE communicationsystem by the random access preamble transmission in the NRcommunication system can be reduced.

In response the receiver receiving an alternative index that specifiesconfiguration information for transmitting the random access preamble,the controller may configure the time domain resource specified by theadditional information by replacing the time domain resource fortransmitting the random access preamble specified by the index with thetime domain resource specified by the additional information.

Since a legacy terminal reads a normal index without reading analternative index, according to the above-described configuration,different PRACH Configuration Indexes can be applied to a legacyterminal and a terminal supporting the above-described configuration.Thus, the legacy terminal and the terminal supporting theabove-described configuration can coexist.

The index that specifies the configuration information for transmittingthe random access preamble may be included in one set between a firstset of one or more indexes that specify default configurationinformation and a second set of one or more indexes that specifyadditional configuration information, and, in response to detecting thatthe index that specifies the configuration information for transmittingthe random access preamble is included in the second set, the controllermay configure the additional configuration information specified by theindex.

According to the above-described configuration, a table for specifying adefault configuration of a random access and a new table that canspecify, as a subframe that corresponds to the default configuration ofthe random access and that is capable of transmitting a random accesspreamble, a subframe that is unable to be specified by the defaultconfiguration can be defined. A random access configuration defined inthe new table can be applied to the terminal.

The time domain resource specified by the additional information may bea resource at a timing that is a same as a timing of a time domainresource for an uplink transmission in another communication system.According to this configuration, an effect of an interference on anothercommunication system by a random access preamble transmission can bereduced.

A communication method executed by a terminal, the communication methodincluding receiving an index specifying configuration information fortransmitting a random access preamble; and configuring, in response toreceiving additional information that specifies a time domain resourcefor transmitting the random access preamble, the time domain resourcespecified by the additional information, the time domain resource beingconfigured by replacing a time domain resource for transmitting therandom access preamble included in the configuration informationspecified by the index with the time domain resource specified by theadditional information.

According to the above-described configuration, for example, in a casewhere a time domain resource for transmitting a random access preambleincluded in default configuration information for transmitting therandom access preamble overlaps a timing of a time domain resource for adownlink transmission in another system, the time domain resource fortransmitting the random access preamble can be configured to be anothertime domain resource specified by the additional information. Bymatching the other time domain resource specified by the additionalinformation with a timing of a time domain resource for an uplinktransmission in another communication system, an effect of aninterference on the other communication system caused by a random accesspreamble transmission can be reduced.

Supplemental Embodiments

While the embodiments of the present invention are described above, thedisclosed invention is not limited to the embodiments, and those skilledin the art will appreciate various alterations, modifications,alternatives, substitutions, or the like. Descriptions are providedusing specific numerical examples to facilitate understanding of theinvention, but, unless as otherwise specified, these values are merelyexamples and any suitable value may be used. Classification of the itemsin the above descriptions is not essential to the present invention, andthe items described in two or more items may be used in combination asneeded, or the items described in one item may be applied (unlessinconsistent) to the items described in another item. The boundaries offunctional units or processing units in the functional block diagram donot necessarily correspond to the boundaries of physical components. Anoperation by a plurality of functional units may be physically performedby one component or an operation by one functional unit may bephysically executed by a plurality of components. For the processingprocedures described in the embodiment, the order of processing may bechanged as long as there is no inconsistency. For the convenience of thedescription of the process, the terminal 10 and the base station 20 aredescribed using functional block diagrams, but such devices may beimplemented in hardware, software, or a combination thereof. Softwareoperated by a processor included in the terminal 10 in accordance withembodiments of the present invention and software operated by aprocessor included in the base station 20 in accordance with embodimentsof the present invention may be stored in a random access memory (RAM),a flash memory (RAM), a read-only memory (ROM), an EPROM, an EEPROM, aregister, a hard disk (HDD), a removable disk, a CD-ROM, a database, aserver, or any other suitable storage medium, respectively.

Notification of information is not limited to the aspects/embodimentsdescribed in the disclosure, and notification of information may be madeby another method. For example, notification of information may beimplemented by physical layer signaling (e.g., Downlink ControlInformation (DCI), Uplink Control Information (UCI), higher layersignaling (e.g., Radio Resource Control (RRC) signaling, Medium AccessControl (MAC) signaling, broadcast information (Master Information Block(MIB), System Information Block (SIB))), or other signals orcombinations thereof. RRC signaling may be referred to as an RRCmessage, for example, which may be an RRC connection setup message, anRRC connection reconfiguration message, or the like.

The aspects/embodiments described in this disclosure may be applied to asystem using at least one of Long Term Evolution (LTE), LTE-Advanced(LTE-A), SUPER 3G, IMT-Advanced, 4th generation mobile communicationsystem (4G), 5th generation mobile communication system (5G), FutureRadio Access (FRA), W-CDMA (Registered Trademark), GSM (RegisteredTrademark), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi(Registered Trademark)), IEEE 802.16 (WiMAX (Registered Trademark)),IEEE 802.20, Ultra-WideBand (UWB), Bluetooth (Registered Trademark), anyother appropriate system, and a next generation system extended based ontheses. Additionally, a plurality of systems may be combined (e.g., acombination of at least one of LTE and LTE-A and 5G) to be applied.

The processing procedures, sequences, flow charts, or the like of eachaspect/embodiment described in this disclosure may be reordered,provided that there is no contradiction. For example, the methodsdescribed in this disclosure present elements of various steps in anexemplary order and are not limited to the particular order presented.

The particular operation described in this disclosure to be performed bybase station 20 may be performed by an upper node in some cases. It isapparent that in a network consisting of one or more network nodeshaving base stations 20, various operations performed for communicatingwith terminal may be performed by at least one of the base stations 20and network nodes other than the base stations 20 (e.g., MME or S-GW canbe considered, however, the network node is not limited to these). Thecase is exemplified above in which there is one network node other thanthe base station 20. However, the network node other than the basestation 20 may be a combination of multiple other network nodes (e.g.,MME and S-GW).

Input and output information, or the like may be stored in a specificlocation (e.g., memory) or managed using management tables. Input andoutput information, or the like may be overwritten, updated, or added.Output information may be deleted. The input information may betransmitted to another device.

The determination may be made by a value (0 or 1) represented by 1 bit,by a true or false value (Boolean: true or false), or by comparison ofnumerical values (e.g., a comparison with a predefined value).

The aspects/embodiments described in this disclosure may be used alone,in combination, or switched along with execution. Notice of a giveninformation (e.g. “X” notice) may also be given by implication (e.g. “nonotice of the given information”), not explicitly.

Software should be broadly interpreted to mean, regardless of whetherreferred to as software, firmware, middleware, microcode, hardwaredescription language, or any other name, instructions, sets ofinstructions, code, code segments, program code, programs, subprograms,software modules, applications, software applications, softwarepackages, routines, subroutines, objects, executable files, executablethreads, procedures, functions, or the like.

Software, instructions, information, or the like may also be transmittedand received via a transmission medium. For example, when software istransmitted from a website, server, or other remote source using atleast one of wireline technology (such as coaxial cable, fiber opticcable, twisted pair, digital subscriber line) and wireless technology(infrared or microwave), at least one of these wireline technology andwireless technology is included within the definition of a transmissionmedium.

The information, signals, or the like described in this disclosure maybe represented using any of a variety of different techniques. Forexample, data, instructions, commands, information, signals, bits,symbols, chips, or the like which may be referred to throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or magnetic particles, opticalfields or photons, or any combination thereof.

The terms described in this disclosure and those necessary forunderstanding this disclosure may be replaced with terms having the sameor similar meanings. For example, at least one of the channels and thesymbols may be a signal (signaling). The signal may also be a message.

As used in this disclosure, the terms “system” and “network” are usedinterchangeably. The information, parameters, or the like described inthe present disclosure may also be expressed using absolute values,relative values from predetermined values, or they may be expressedusing corresponding separate information. For example, radio resourcesmay be those indicated by an index.

The name used for the parameters described above are not restrictive inany respect. In addition, the mathematical equations using theseparameters may differ from those explicitly disclosed in thisdisclosure. Since the various channels (e.g., PUCCH or PDCCH) andinformation elements can be identified by any suitable name, the variousnames assigned to these various channels and information elements arenot in any way limiting.

In this disclosure, the terms “Base Station,” “Radio Base Station,”“Fixed Station,” “NodeB,” “eNodeB (eNB),” “gNodeB (gNB),” “AccessPoint,” “Transmission Point,” “Reception Point,” “Transmission/ReceptionPoint,” “Cell,” “Sector,” “Cell Group,” “Carrier,” “Component Carrier,”and the like may be used interchangeably. The base stations may bereferred to in terms such as macro-cell, small-cell, femto-cell, orpico-cell.

The base station can accommodate one or more (e.g., three) cells. Wherethe base station accommodates a plurality of cells, the entire coveragearea of the base station can be divided into a plurality of smallerareas, each smaller area can also provide communication services bymeans of a base station subsystem (e.g., an indoor small base station(RRH) or a remote Radio Head). The term “cell” or “sector” refers to aportion or all of the coverage area of at least one of the base stationand base station subsystem that provides communication services at thecoverage.

In this disclosure, terms such as “mobile station (MS: Mobile Station)”,“user terminal”, “user equipment (UE: User Equipment”, or “terminal” maybe used interchangeably.

The mobile station may be referred to by one of ordinary skill in theart as a subscriber station, a mobile unit, a subscriber unit, awireless unit, a remote unit, a mobile device, a wireless device, awireless communication device, a remote device, a mobile subscriberstation, an access terminal, a mobile terminal, a wireless terminal, aremote terminal, a handset, a user agent, a mobile client, a client, orsome other suitable term.

At least one of a base station and a mobile station may be referred toas a transmitter, receiver, communication device, or the like. At leastone of a base station and a mobile station may be a device installed ina mobile body, a mobile body itself, or the like. The mobile body may bea vehicle (e.g., a car or an airplane), an unmanned mobile (e.g., adrone or an automated vehicle), or a robot (manned or unmanned). Atleast one of a base station and a mobile station includes a device thatdoes not necessarily move during communication operations. For example,at least one of a base station and a mobile station may be an IoT(Internet of Things) device such as a sensor.

In addition, the base station in the present disclosure may be read bythe user terminal. For example, various aspects/embodiments of thepresent disclosure may be applied to a configuration in whichcommunication between base stations and user terminals is replaced withcommunication between multiple user terminals (e.g., may be referred toas Device-to-Device (D2)) or Vehicle-to-Everything (V2X). In this case,a configuration may be such that the above-described function of thebase station 20 is included in the user terminal 10. The terms “up” and“down” may also be replaced with the terms corresponding toterminal-to-terminal communication (e.g., “side”). For example, anuplink channel, a downlink channel, or the like, may be replaced with asidelink channel.

Similarly, the user terminal in the present disclosure may be replacedwith the base station. In this case, a configuration may be such thatthe above-described function of the user terminal 10 is included in thebase station 20.

The term “connected” or “coupled” or any variation thereof means anydirect or indirect connection or connection between two or more elementsand may include the presence of one or more intermediate elementsbetween two elements “connected” or “coupled” with each other. Thecoupling or connection between the elements may be physical, logical, ora combination of these. For example, “connection” may be replaced with“access”. As used in the present disclosure, the two elements may beconsidered as being “connected” or “coupled” to each other using atleast one of the one or more wires, cables, and printed electricalconnections and, as a number of non-limiting and non-inclusive examples,electromagnetic energy having wavelengths in the radio frequency region,the microwave region, and the light (both visible and invisible) region.

The reference signal may be abbreviated as RS (Reference Signal) or maybe referred to as a pilot, depending on the standards applied.

As used in this disclosure, the expression “based on” does not mean“based on only” unless otherwise specified. In other words, theexpression “based on” means both “based on only” and “at least basedon.”

When the terms “include”, “including” and variations thereof are used inthe present disclosure, these terms are intended to be inclusive,similar to the term “comprising”. Moreover, the term “or” as used inthis disclosure is not intended to be an exclusive-OR.

A radio frame may be formed of one or more frames in the time domain. Inthe time domain, each of the one or more frames may be referred to as asubframe. A subframe may further be formed of one or more slots in thetime domain. A subframe may be a fixed time length (e.g., 1 ms) thatdoes not depend on numerology.

The numerology may be a communication parameter to be applied to atleast one of transmission or reception of a signal or a channel. Thenumerology may represent, for example, at least one of a subcarrierspacing (SCS: SubCarrier Spacing), a bandwidth, a symbol length, acyclic prefix length, a transmission time interval (TTI: TransmissionTime Interval), a symbol number per TTI, a radio frame configuration, aspecific filtering process performed by a transceiver in a frequencydomain, a specific windowing process performed by a transceiver in atime domain, or the like.

A slot may be formed of, in a time domain, one or more symbols (OFDM(Orthogonal Frequency Division Multiplexing) symbols, SC-FDMA (SingleCarrier Frequency Division Multiple Access) symbols, etc.). A slot maybe a unit of time based on the numerology.

A slot may include a plurality of mini-slots. In a time domain, eachmini-slot may be formed of one or more symbols. A mini-slot may also bereferred to as a sub-slot. A mini-slot may be formed of fewer symbolsthan those of a slot. The PDSCH (or PUSCH) transmitted in a unit of timethat is greater than a mini-slot may be referred to as PDSCH (or PUSCH)mapping type A. The PDSCH (or PUSCH) transmitted using a mini-slot maybe referred to as PDSCH (or PUSCH) mapping type B.

Each of the radio frame, subframe, slot, mini-slot, and symbolrepresents a time unit for transmitting a signal. The radio frame,subframe, slot, mini-slot, and symbol may be called by respectivedifferent names.

For example, one subframe may be referred to as a transmission timeinterval (TTI: Transmission Time Interval), a plurality of consecutivesubframes may be referred to as TTI, or one slot or one mini-slot may bereferred to as TTI. Namely, at least one of a subframe and TTI may be asubframe (1 ms) in the existing LTE, may be a time interval shorter than1 ms (e.g., 1 to 13 symbols), or a time interval longer than 1 ms. Notethat the unit representing the TTI may be referred to as a slot, amini-slot, or the like instead of a subframe.

Here, the TTI refers to, for example, the minimum time unit ofscheduling in radio communication. For example, in the LTE system, thebase station performs scheduling for allocating radio resources (such asa frequency bandwidth or transmission power that can be used in eachterminal 10) in units of TTIs to each terminal 10. Note that thedefinition of the TTI is not limited to this.

The TTI may be a transmission time unit, such as a channel coded datapacket (transport block), a code block, or a codeword, or may be aprocessing unit for scheduling, link adaptation, or the like. Note that,when a TTI is provided, a time interval (e.g., a symbol number) ontowhich a transport block, a code block, or a code ward is actually mappedmay be shorter than the TTI.

Note that, when one slot or one mini-slot is referred to as a TTI, oneor more TTIs (i.e., one or more slots or one or more mini-slots) may bethe minimum time unit of scheduling. Additionally, the number of slots(the number of mini-slots) forming the minimum time unit of schedulingmay be controlled.

A TTI with a time length of 1 ms may be referred to as an ordinary TTI(TTI in LTE Rel. 8-12), a normal TTI, a long TTI, an ordinary subframe,a normal subframe, a long subframe, a slot, or the like. A TTI that isshorter than a normal TTI may be referred to as a shortened TTI, a shortTTI, a partial TTI (partial TTI or fractional TTI), a shortenedsubframe, a short subframe, a mini-slot, a sub-slot, a slot, or thelike.

Note that a long TTI (e.g., a normal TTI, or a subframe) may be replacedwith a TTI with a time length exceeding 1 ms, and a short TTI (e.g., ashortened TTI) may be replaced with a TTI with a TTI length that isshorter than the TTI length of the long TTI and longer than or equal to1 ms.

A resource block (RB) is a resource assignment unit in the time domainand the frequency domain, and may include one or more consecutivesubcarriers in the frequency domain. A number of subcarriers included ina RB may be the same irrespective of numerology, and may be 12, forexample. The number of subcarriers included in a RB may be determinedbased on numerology.

Additionally, the resource block may include one or more symbols in thetime domain, and may have a length of one slot, one mini-slot, onesubframe, or one TTI. Each of one TTI and one subframe may be formed ofone or more resource blocks.

Note that one or more RBs may be referred to as a physical resourceblock (PRB: Physical RB), a subcarrier group (SCG: Sub-Carrier Group), aresource element group (REG: Resource Element Group), a PRB pair, a RBpair, or the like.

Additionally, a resource block may be formed of one or more resourceelements (RE: Resource Element). For example, 1 RE may be a radioresource area of 1 subcarrier and 1 symbol.

A bandwidth part (BWP: Bandwidth Part) (which may also be referred to asa partial bandwidth, or the like) may represent, in a certain carrier, asubset of consecutive common RB (common resource blocks) for a certainnumerology. Here, the common RB may be specified by an index of a RBwhen a common reference point of the carrier is used as a reference. APRB may be defined in a BWP, and may be numbered in the BWP.

The BWP may include a BWP for UL (UL BWP) and a BWP for DL (DL BWP). Fora UE, one or more BWPs may be configured within one carrier.

At least one of the configured BWPs may be active, and the UE is may notassume that a predetermined signal/channel is communicated outside theactive BWP. Note that “cell,” “carrier,” or the like in the presentdisclosure may be replaced with “BWP.”

The structures of the above-described radio frame, subframe, slot,mini-slot, symbol, and the like are merely illustrative. For example,the following configurations can be variously changed: the number ofsubframes included in the radio frame; the number of slots per subframeor radio frame; the number of mini-slots included in the slot; thenumber of symbols and RBs included in the slot or mini-slot; the numberof subcarriers included in the RB; and the number of symbols, the symbollength, the cyclic prefix (CP: Cyclic Prefix) length, and the likewithin the TTI.

In the present disclosure, where an article is added by translation, forexample, “a,” “an,” and “the” of English, the disclosure may includethat the noun following these articles is plural.

In this disclosure, the term “A and B are different” may mean “A and Bare different from each other.” Note that the term may mean “A and B aredifferent from C.” Terms such as “separated” or “combined” may beinterpreted similar to “different.”

While the present invention is described in detail above, those skilledin the art will appreciate that the invention is not limited to theembodiments described herein. The present invention may be implementedas modifications and variations without departing from the gist andscope of the present invention as defined by the scope of the claims.Accordingly, the description herein is for purposes of illustration andis not intended to have any limiting meaning with respect to the presentinvention.

LIST OF REFERENCE SYMBOLS

-   10 terminal-   110 transmitter-   120 receiver-   130 controller-   20 base station-   210 transmitter-   220 receiver-   230 controller-   1001 processor-   1002 memory-   1003 storage-   1004 communication device-   1005 input device-   1006 output device

1.-6. (canceled)
 7. A terminal comprising: a receiver that receives anindex that specifies first configuration information for transmitting arandom access preamble; and a controller that uses, in response to thereceiver receiving the index, the first configuration information fortransmitting the random access preamble, wherein, when a value of asubframe number included in the first configuration informationspecified by the index in a case where a value of the index is greaterthan or equal to a specific value is replaced with a value of a subframenumber included in second configuration information specified by aspecific index with a value that is less than the specific value, thefirst configuration information is identical to the second configurationinformation.
 8. The terminal according to claim 7, wherein the indexwith the value that is greater than or equal to the specific value isspecified by a specific field included in a specific signaling message.9. The terminal according to claim 7, wherein the first configurationinformation for transmitting the random access preamble is configurationinformation corresponding to a specific frequency range and a TimeDivision Duplex (TDD) method.
 10. The terminal according to claim 8,wherein the specific signaling message is a RACH-ConfigGenericinformation element, the specific field is aprach-ConfigurationIndex-v16xy, and the specific value is
 256. 11. Abase station comprising: a controller that configures an index thatspecifies first configuration information of a random access preamble,wherein the first configuration information is to be configured for aterminal; and a transmitter that transmits the index to the terminal,wherein, when a value of a subframe number included in the firstconfiguration information specified by the index in a case where a valueof the index is greater than or equal to a specific value is replacedwith a value of a subframe number included in second configurationinformation specified by a specific index with a value that is less thanthe specific value, the first configuration information is identical tothe second configuration information.
 12. A communication methodexecuted by a terminal, the method comprising: receiving an index thatspecifies first configuration information for transmitting a randomaccess preamble; and using, in response to receiving the index, thefirst configuration information for transmitting the random accesspreamble, wherein, when a value of a subframe number included in thefirst configuration information specified by the index in a case where avalue of the index is greater than or equal to a specific value isreplaced with a value of a subframe number included in secondconfiguration information specified by a specific index with a valuethat is less than the specific value, the first configurationinformation is identical to the second configuration information.